VLF waves from ground-based transmitters observed by the Van Allen Probes: Statistical model and effects on plasmaspheric electrons

Abstract

Whistler mode very low frequency (VLF) waves from powerful ground-based transmitters can resonantly scatter energetic plasmaspheric electrons and precipitate them into the atmosphere. A comprehensive 4 year statistics of Van Allen Probes measurements is carried out to assess their consequences on the dynamics of the inner radiation belt and slot region. Statistical models of the measured wave electric field power and of the inferred full wave magnetic amplitude are provided as a function of L, magnetic local time, season, and Kp over L = 1–3, revealing the localization of VLF wave intensity and its variation with geomagnetic activity over 2012–2016. Since this VLF wave model can be directly used together with existing hiss and lightning-generated wave models in radiation belt simulation codes, we perform numerical calculations of the corresponding quasi-linear pitch angle diffusion rates, allowing us to demonstrate the crucial role played by VLF waves from transmitters in energetic electron loss at L < 2.5.